Multi-speaker systems are widely available in audio, video, and entertainment systems today. For example, quadratic four-speaker systems and 5.1 systems provide listeners with more enjoyable multi-media experiences compared to traditional stereo systems. However, there are large quantities of stereo audio content that are available and that are currently being produced. This stereo audio content does not fully utilize the advantages of multi-speaker systems such as quadratic four-speaker systems and 5.1 systems. There have been various difficulties in attempting to better utilize multi-speaker systems to give more listening pleasure when reproducing stereo audio content than straightforward stereo playback.
Many techniques have been developed to attempt to better render stereo audio content utilizing more than two speakers to create a surrounding sound field. Many of these techniques rely on the belief that in-phase information between two signals should be provided at the center front of a listener, while out-of-phase information should be provided to the rear of the listener.
Many of these techniques also suffer from various problems. These problems may include relatively high computational costs, an inability to efficiently handle input signals that have more than one dominant signal, or undesirable effects in the rendering of the stereo audio content (such as unnatural sound effects). Many conventional techniques cannot perform multi-speaker rendition of stereo audio content that achieves good channel separation with minimal and scalable computational costs, while being able to efficiently handle input signals having multiple dominant signals.